What’s the piezoelectric ceramic filter?

A filter is a circuit or device that is selective to the frequency of the signal. To separate a signal at a certain frequency or a signal in a certain frequency band from a signal with a wide frequency range, a filter is required. For example, in multi-channel communication, if two or more people on a line talk at the same time and want to avoid interference, they need to be processed with piezo ceramics.the usual method is to transmit each person's voice signal through the same line with different carrier frequencies. A filter is used at the receiving end to separate each carrier's carrier frequency from a number of carrier frequencies. In recent years, the rapid development of mobile communication, satellite communication and optical communication, and computer technology has dramatically increased the density of communication devices and the congestion of radio spectrum. The simultaneous operation of a large number of communication devices results in a large amount of interference and noise in the passband of the receiving terminal. To solve this problem, you must also use a filter of good stability piezoelectric ceramic. Communication systems are one of the most widely used areas of filters. It is also widely used in other fields such as telemetry, navigation and radio measurement.

At present, the development direction of communication equipment is miniaturization and integration to ensure flexibility and convenience in practical use.There are many kinds of filters and types. piezo ceramic bimorph filters are one kind of filters, which are important aspects of piezoelectric ceramic applications. It has the characteristics of small size, light weight, low price, and easy to design and manufacture products with excellent performance according to the requirements of use, and its application is more and more extensive.

When the signals of the same amplitude and different frequencies of piezoelectric ultrasonic tranducer pass through the filter, the amplitude of the output signal of the filter will vary with the frequency, that is, the attenuation of the signal to the signals of different frequencies is different. Passband: The frequency at which the attenuation is small and the signal passes; the stopband: the frequency of the band that has a large attenuation and hardly let the signal pass. Cutoff frequency: The frequency at the passband or stopband boundary; transition zone: the band from passband to stopband.Filter classification According to the passband range, the filter can be divided into the following categories: the low-pass filter has a passband below the cutoff frequency and a stopband above the cutoff frequency. The high pass filter of wholesale piezoelectric transducer has a pass band above the cutoff frequency and a stop band below the cutoff frequency. The bandpass filter has a passband between the two cutoff frequencies and a stopband outside the two cutoff frequencies. The band stop filter has a pass band outside the two cutoff cutoff frequencies and a stop band between the two cutoff frequencies.

According to the structural form of the filter element combination, it can be further divided into a ladder filter and a bridge filter. A single-section filter in which the main components of the filter are combined into a T-shape or a ∏-type structure, and a multi-section filter in which a T-shaped or a ∏-type single-section filter are linked is referred to as a ladder filter. A filter of piezo electric ceramic that combines components into a bridge circuit structure is called a bridge filter, also called a lattice filter.